Combination well blowout preventer

ABSTRACT

The disclosure concerns unusually advantageous apparatus used in controlling and preventing well blowouts, and utilizing novel plug-valve sealing and operating structure, and further as related to the location and housing of an inwardly constrictable packer annulus.

adg well owouts, and utilizing novel plug-valve sealing and operatingstructure, and further as related to the location and h an inwardlyconstrictable packer annulus.

251/1 251/1 X 277/73 25l/315X unusually ousing of References CitedUNITED STATES PATENTS 7/1934 Wickersham et a1 disclosure concernsvantageous apparatus used in controlling and preventin bl 2,313,1773/1943 Sprague...4.l.,........ 2,609,836 9/1952 Knox......,...m..3,124334 3/1964 Szohatzkyl.....h...,...l...

Primary Examiner-A1an Cohan Assistant Examiner-Richard GerardAttorney-White & Haefliger ABSTRACT: The

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ATENTED JUN29 197i SHEET t 0F 4 Jn w MMM 75 e m M 7 I mi GMM wcoMaiNArroN WELL arowotnr raaven'rnn BACKGROUND or THE INVENTION Thisinvention relates generally to oil well drilling operations, and moreparticularly concerns apparatus useful in controlling and preventingwell blowouts.

Well blowout control and prevention equipment may be categorized aseither of the type which closes the well by constricting about apparatussuch as a drill string run in the well, or of the type which positivelyblocks the entire well passage. The former equipment is generallydescribed in U.S. Pat. No. 2,609,836, whereas the latter equipment isexemplified by safety valves and ram-type preventers. In many cases itis desired to incorporate both types of equipment in wellhead apparatusfor increased safety; however, the possible combination ofwell-constricting equipment with rotary plug safety valve equipment atthe wellhead (with or without ram-type preventers) has been consideredas presenting certain difficulties. These include the difficulty ofgaining access to the plug stopper for inspection and replacementpurposes; the problem of satisfactorily sealing off between the rotarystopper and the housing therefor; the problem of particle (such as sand)accumulation between the stopper and its housing; and the difficulty ofaccommodating the safety valve structure to combination with the wellpassage constricting apparatus.

BRIEF SUMMARY OF THE INVENTION It is a major object of the invention tocombine well passage constricting apparatus with safety valve structurein such manner as will alleviate the above problems and difiiculties. Itis another object-of the invention to provide improved sealing ringstructure for a safety valve employing a load-transmitting trunnion ortrunnions, the ring sealing off between the latter and the valve housingin such a way as to enable rotation of the valve stopper free of thesealing ring while remaining easily replaceable after disconnection ofhousing sections between which the ring structure also seals off.

As respects the combined safety valve and well passage constrictingequipment, the invention basically comprises a housing structuredefining vertically spaced chambers; an inwardly constrictable packerannulus in one of the chambers for forming therewith a vertical passagethrough which tubular goods may be run; an annular piston movableupwardly in that one chamber to constrict the packer for reducing theopening; a plug stopper having a through opening and mounted to rotatein another of the chambers tobeing the stopper opening into and out ofregistration with the passage; and the housing structure including asection at the side of the plug opposite that one chamber and which isremovable to provide direct access to the plug. Accordingly, the stoppermay be easily removed for replacement of seal structure to be described.Typically, there is space in the stopper chamber with elastomer-sealingmeans filling that space between the stopper and chamber inner wall, thesealant extending annularly about the through opening in the stopperwhen the latter is in flow-passing registration with the passage,whereby sand and other particles cannot fill into that space and impedestopper rotation. This is very important in respect of subsea drillingoperations, where reliability is critical. Further, a metallic seal ringmay be provided to form a portion of the passage adjacent the plug, withwhich the metal seal has sliding and sealing contact, that ring actingto confine the elastomer-scaling means against pressure induceddisplacement from that space. In addition, the elastomer-sealing meansmay be formed at two generally hemispherical sections, which areremovable for replacement when the housing section is removed, asdescribed. Those sections may have terminals so located as not to beexposed to line pressure during rotation of the stopper opening incommunication with those terminals; also retainer structure may blockinward deflection of those terminals. Finally, stoppersupportingtrunnions are accommodated by the housing and sealing structuredescribed, the trunnions being removable with the stopper, and therebeing operator means at the housing exterior and connected to rotate onetrunnion to rotate the stopper between limits, as provided by operatorpiston means.

As respects sealing of the valve assembly in the housing or body, theinvention comprises, in combination with the stopper and trunnion, anannulus such as a sleeve extending about the trunnion, and seal ringstructure having a first portion extending closely about the sleeve toseal off between the latter and body; and a second portion extendingabout the stopper in nonsealing relation therewith to permit stopperrotation while the second portion seals off the body sections, as willbe described. Typically, the ring structure includes a third portionlike the first portion and extending about a second sleeve received overa second trunnion integral with the stopper, the trunnions rotating withthe stopper but within the sleeves.

Another aspect of the invention concerns the provision of a seal ringstructure as described, to be used with a plug stopper having trunnionsand sleeves received on the trunnions.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects andadvantagesof the invention as well as the details of an illustrativeembodiment, will be more fully understood from the following detaileddescription of the drawings, in which:

FIG. l is an elevation taken in section, showing the overall invention;

FIG. 2 is an elevation taken in section on line2-2 of FIG. 1;

FIG. 3 is a perspective showing of the plug stopper of FIGS. 11 and 2,with seal ring structure mounted on sleeves on the stopper trunnions;

FIG. 4 is an end elevation of the FIG. 3 assembly taken on line 4-4 ofFIG. 3;

FIG. 5 is a top plan view of the FIG. 3 assembly, taken on line 5-5 ofFIG. 3;

FIG. 6 is a perspective view showing the seal ring structure;

FIG. 7 is an elevation showing the blowout control equipment of theinvention installed in subsea wellhead assembly;

and

FIG. 3 is an elevation showing a modified safety valve seal arrangement.

DESCRIFTION OF THE PREFERRED EMBODIMENTS Turning to FIG. l, the controlhead or preventer assembly, generally indicated at 10, includes a bodymember 11, having concentric bores 12, 113 and 14, which are ofprogressively increased diameters. Cap 16 is releasably held to the bodymember by screw-threaded connection 17 in such a position that the fade19 of cap flange 20 engages the upper end 2i. of the body member 11, thecap and body member being packed off at 22. Cap 16 has a bore 23 whichis of the same diameter and is concentric with body bore 12. Sunk in theupper face of cap 16 are boltholes 24 for the attachment of equipmentthereabove. The annular groove 25, in that upper face, is adaptedtoreceive a sealing ring for sealing engagement with said equipment.

The body member 11 has an attachment flange 27 whereby connection ismade through bolts 28 to the flange 29 of body lower section 30 definingbore 12. i

Cap 16 has an internal annular flange 35 which defines the downwardcontinuation of bore 23, and a peripheral flange 36 which defines bore37, said bore 37 being concentric with all the body member boresidentified above.

The body 11 has an annular, upstanding flange 38 which engages thepacker-actuating member 39 at 40 to limit the extent of downwardmovement of said member. The actuator 39 has a piston portion 41, havingpiston fit in bore 14, and piston portion 42 which has piston fit inbore 13. The actuator is extended upwardly at 43, extension 43 havingpiston fit in the bore 37. Sealing rings 44, 45 and 46 are providedbetween piston portions 412, 41 and 43, respectively, and the respectivecylinder-defining walls which receive those portions.

Piston 41 divides body bore 141 into upper (first) and lower (second)cylinders or pressure chambers 47 and 48, ports 49 and 50 opening,respectively, from those chambers. External pipes 51 and 52 open toports 49 and 50 respectively. Note that the outer diameters 14 ofchambers 47 and 48 are equal, and the inner diameters l3 and 37 of thesechambers are equal, for balancing purposes.

The actuator 39 has a downwardly and inwardly tapering conical bore 53,and the actuator portion 43 which defines this bore may be consideredbroadly as an internal, conical wedge, or as a packer-constrictingelement.

Packet P includes a massive annulus or sleeve 55 of plastic and,preferably, resilient material such as rubber or Neoprene. in mostinstances, it is intended that a single packer be adapted for repeatingopening and closing operations, and therefore it is preferable that ithave relatively high resilient characteristics, so it may beself-resorting to open position when the constricting force is removed.From this point on in the description, it will be assumed that thepacker has such resilient characteristics, but this assumption is notconsidered as limitative on my broader claims. It has been found thatrubber having a durometer hardness of about 75 is suitable for generaluse in the packer but, again, this specification of relative hardness isnot to be considered as limitative. The packer is shown as an u nsplit,continuous annulus, but it will be understood that the disclosure is notlimited to a packer wherein there is no split, so long as there is noangularly extending gap interrupting the continuity of the packer attimes when it is radially contracted into sealing engagement withmembers positioned within its bore.

included in the makeup of the packer is a series of rigid,rubber-flow-control elements 56 individually movable bodily with therubber in its movement of radial contraction and expansion and also, toa limited extent, movable individually with respect to the rubber aswill later appear. Taken together, the rigid control elements may beconsidered as a radially expansible and contractable armature embeddedand bonded with annulus 55.

Molded annulus 55 has an outer conical face 57 which is complementary toactuator bore 53, and a bore i; which has a central, substantiallycylindrical portion 59 and oppositely inclining upper and lower portions69 and 61, respectively; the outward flare, in each case being towardthe associated end of the annulus.

It will be seen that each element 56 comprises top and bottom plates 63and 64, respectively, rigidly connected by vertical rib 65, the outerface 67 of the rib having taper as in dicated. Plates 63, 64 may beconsidered as transverse flanges on rib 65. Elements 56, which may be ofsteel, bronze, or any other suitable rigid material, are preferablypositioned in the rubber at the time of molding and, preferably, therubber and the elements are bonded together by the use of suitablebonding agent during the molding process. The plates of the controlelements are sectorial in shape, as viewed in plan, and are ar ranged ina circular series, with spaces left between the opposing side edges ofthe plates, both top and bottom. The plates are so sized that the twoopposed side edges of adjacent elements are spaced apart, it followingthat as the elements move radially inward, the spaces between these,from end-to-end, diminish equally in width, so there is no prematureinterference of the plates at their inner ends and so the rubber whichmay flow between the plates during the constriction of the annulus willnot be pinched off at the radially inward ends ofthe plates. See US.Pat. No. 2,609,836.

The annulus 55 is molded so its outer annular portion 72 projectsradially outward beyond the outer faces of the plates, it following thatthese metallic faces do not engage the wall of the actuator bore 53. Forpurposes of later description, consider annular portion 72 as being thatportion which extends radially from face 57 to the outer faces 67 ofribs 65.

The packer is lowered, while cap 16 is detached, into the position ofH0. 1, the annulus 55 nicely fitting the upper por tion of bore 53without requiring appreciable radial constriction of the annulus. Forpositively limiting the downward movement of the annulus, a stop isprovided in the form of tube 74 which is retained in housing bore 15.The upper end of the tube provides the packer stop. The bore '75 of thistube is of the same diameter as bores 12 and 23, and the tube isannularly spaced from both piston portion 42 and the lower end ofactuator wedge portion 43. Ports 76 open from bore 75 to chamber 77,which latter is annularly defined by the tube 74 and the sleeve 80,while it is retained endwise by body wall 78 and the lower end ofsleeve80.

When cap 16 is subsequently secured in place, its horizontalundersurface 79 provides a stop for limiting upward movement of thepacker, the upper plates 63 of control elements 56 sliding over thissurface as the packer is radially constricted or expanded. Upper end oftube 74 and cap surface 79 thus form vertically spaced stops whichprevent appreciable vertical movement of the packer with relation to thebody member ll. Packer P is thus confined within an upper chamber formedin the housing.

It will be seen that the radial constriction of the packer isaccomplished by virtue of relative vertical movement between the packerand the actuator. While the illustrated embodiment shows this relativemovement as brought about by holding the packer against verticalmovement with respect to the body member and then moving the actuatorvertically with respect to the housing and packer, it will be understoodthe arrangement and operation may be reversed.

The sleeve 80 may be considered as part of the housing structure ill, towhich it is retained by the fastener 81. The sleeve 80 and body ill,together with actuator piston portion 42 form a third chamber 82 toreceive control pressure fluid (as via porting 83 and pipe 84) acting tourge the actuator upwardly in at least partly counterbalancing relationto the downward force exertion on the actuator. See in this regard mycopending application for US. Letters Patent entitled WELL PRESSURECOMPENSATED WELL BLOWOUT PREVENTER, Ser. No. 785,891 and now U.S. Pat.No. 3,533,468.

Referring again to PK}. 1, a hydropneumatic accumulator is shown ascommunicating with pipes 5i and 52 via a suitable pressure regulator 91and four-way valve 92.. In one position ofthe latter, pressure fluid isdelivered to pipe 51, and pressure fluid in pipe 52 is exhausted at 93to the sea. in the alternate position of the valve 92, pressure fluid isdelivered to pipe 52 and fluid in pipe 51 is exhausted to the sea. Asuitable electric prime mover 94 controls valve Q2 and a suitablecontrol 95 for the regulator may be surface operated to set the pressureapplied to pipes 52 and 52. Similarly, pressure may be supplied to pipe84 via regulator 96 and four-way valve 97. Controls for the regulatorand valve are indicated at 93 and 99 and may be electrically operatedfrom the surface, to result in selected pressure applications to chamber82, a cable to the surface being indicated at Control 98 for regulator96 may be connected via ll} to annulus or passage 85 to be responsive tomud e packer, so as to effect transmission of regulated pressv .ochamber 82, in response to changes in mud pressure.

Reference to FIG. 7 shows the control assembly 10 connected in subseablowout preventer stack F including a unit it? above a series ofram-type preventers 103.. A riser system E02 extends above the stack lnd is connected thereto by a wellhead connector 103. Riser pipe extendsto the sea surface, and typically to a drilling barge $.64, or otherinstallation. Stack MM) and riser 102 are illustrative only, and maycarry the pressure vessel 90 and associated piping and controls referredto above.

A lower chamber in the housing llli contains a plug stopper 13l mountedto rotate about horizontal axis 132. Such rotation brings the throughopening 133 in the stopper into and out of registration with thevertical passage 134 in the housing. In this regard, the lower section30 of the body or housing is removable, as by disconnection of flange 2%from body portion 27 afforded by removal of bolts 28, thereby to producedirect access to the plug stopper enabling removal of the latter.

The stopper is supported for rotation by the trunnions or shafts 135 and136 which project oppositely and in alignment with axis 132. Annuli, asfor example bearing sleeves 137 and 138 extend about the trunnions andare received in the bores 139 and 140, the upper halves of which areformed by body portion 27, and the lower halves of which are formed bybody lower portion 30. Accordingly, upon disconnection of the latter,the sleeves and trunnions are downwardly removable along with the plugstopper, for repair and replacement. This may be accomplished while theflange 1411 of body section remains bolted to wellhead structuretherebeneath (bolts 142 affording such connection) the body section 27and wellhead structure thereabove being elevated.

The space between the plug stopper an inner wall portions 144 and 145 ofthe body is filled with elastomer-sealing means extending annularlyabout the through opening 133 when the latter is in FIG. 1 position, inregistration with passage 134. Such sealing means may typically compriseupper and lower hard rubber hemispheres 1416 and 1 17 which areinterengaged along a horizontal plane through axis 132. As seen, thosehemispheres extend closely about the inner annular terminals 148 of thenonrotary sleeves 137 and 138 which engage and center the stopper withinthe housing chamber. O-rings 149 seal off between those terminals andthe trunnions. Like rubber hemispheres 146 and 147 prevent ingress ofsand or foreign matter into the space between the stopper and bodyduring working of the well, eliminating a source of possible malfunctionof the plug stopper.

Metallic seal rings 150 and 151 carried by the rubber hemispheres areslidably received in body bores 152 and 153 and form portions 134a and13412 of the passage 134 adjacent the plug stopper 131. These rings havemetal-to-metal sealing contact at 154 and 155 with the stopper surface,and act to confine the elastomer material 146 and 147 against pressureinduced displacement from the space between the stopper and chamberwall, particularly when the stopper opening is rotated out ofregistration with passage 134. Note that fluid pressure in the well isapplied to end faces 156 and 157 of the seal rings to maintain the ringsin contact with the stopper surface.

Another aspect of the invention has to do with seal ring structurehaving a portion or portions extending about the trunnion sleeve orsleeves to seal off between the latter and the body bores 139 and 141),and another portion extending about the stopper in nonsealing relationto permit stopper rotation while that ring portion seals off against thebody (and specifically between the opposed body faces proximate thehorizontal plane through axis 132). In this regard, reference to FIGS.3-6 show the seal O-ring portions 160 and 161 which are spaced apart andsized to fit about the sleeve terminals 148 and to extend in uprightplanes. The seal ring structure also includes portions 162interconnecting O-rings 161) and 161 and defining a plane normal to theplanes 160 and 161, as well as coincident with the horizontal planethrough axis 132. Portions 162 are alike and sized to extend about thestopper with clearance therebetween (as seen in FIG. 5) to permitstopper rotation. Portions 1152 are retained or clamped between the bodyelements 27 and 29, as appears in FIG. 41, to seal off therebetween.

Upon removal of the stopper, trunnions and sleeves as described above,the unitary elastomer seal structure 160, 161 and 162 is also removedand may then be replaced if necessary. By molding seal structure 160,161 and 162 as a unit, there is no chance for well fluid outward leakage(or sea water inward leakage) past unconnected segments of installedseal, and this helps to make possible and practical the housing construction by which the plug stopper and hemispheres 146 and 147 may beremoved and replaced, as described.

Finally, operator means is provided at one side of the housing structureto transmit rotation to the plug stopper. The latter includes a piniongear 170 keyed at 171 to extension 172 of the trunnion 135 as seen inFIGS. 1 and 2. Gear 170 is carried within a housing 173 bolted at 215 tobody section 30 and to body 11 so as to be removable therefrom and withthe stopper.

Located within housing 173 are upper and lower racks 175 and 176 meshingwith the pinion gear and integral with pistons 177 and 173. The latterare reciprocable horizontally within cylinders 1'79 and 1811 formedwithin and by the housing structure as shown, there being endcaps 181and 182 closing the cylinders at their heads. As fluid pressure isadmitted to drive piston 177 to the left in FIG. 2, the gear is rotatedby rack 175 and drives rack 176 and piston 178 to the right, therebyexhausting fluid from the space between piston 178 and cap 182. Caps 181and 182 limit turning of the plug stopper to an angular range of aboutthese caps, together with caps 181a and 1820 being engaged by oppositeends of the pistons. Rollers 210 and 211 resist side loading of thepistons imposed by the pinion gear 1711.

Pressure is transmissible from vessel 90 alternately to ports 191) and191 under the control of four-way valve 192. An electrically energizedvalve driver is seen at 195. Control lines for this element is seen at196, leading to the surface via cable 199.

Referring now to FIG. 8, the construction of the safety valve apparatusis similar to that of FIG. 1, with corresponding parts bearing the sameidentifying numbers. The modified elastomer seals 1416a and 147a arealike, and again function to block ingress of sand or other foreignmatter into the space between the stopper and the body. However, in thiscase the seals have annular terminals 1 16b and 1417b which we mu tuallyproximate and extend about the stopper at an angle relative to thepassage axis 211) characterized in that the stopper opening 133 isdirectly exposed to the terminals only when that opening is rotated outof communication with the passage 134. As a result the pressure of fluidin passage 134 does not gain direct access to the split or clearance 211between those terminals, which access could otherwise result in pressureinduced inward displacement of those terminals into the stopper openingand subsequent excessive wear thereof as the stopper edge 212 traversedthe clearance 211 during stopper rotation toward open position in thedirection of arrow 213. As illustrated, that trailing edge traversesclearance 211 just after or at the same time that leading edge 21 1 ofthe opening 133 traverses the seal ring 151 and comes into communicationwith the passage 134. The angle made by the plane of clearance 211 withaxis 210 is designated at X. That plane also contains the transverseaxis 132 of stopper rotation as is clear from FIG. 8.

Note also the provision of retainer means extending in the modifiedhemispheric seals 1 16a and 147a and restraining the terminals 14612 and1471) against inward deflection toward the stopper as the stopperopening traverses those terminals. In the illustrated example suchretainer means comprise metal inserts 215 and 216 extending or embeddedin these terminals and about the stopper, with insert portions 215a and216a looping about the trunnions and 136 and sleeves 137 and 138.

We claim:

1. In well blowout prevention apparatus, the combination comprising a.housing structure defining vertically spaced intercommunicatingchambers,

b. an inwardly constrictable packer annulus in one of said chambers forforming therewith a vertical passage through which well tools may berun,

c. an annular piston movable upwardly in said one chamber to constrictthe annulus for sealing engagement with a well tool in said passage,

d, a plug stopper having a through opening and mounted to rotate inanother of said chambers to bring said through opening into and out ofregistration with said passage,

c. said housing structure including a section at the side of the plugopposite said one chamber and which is remova' ble to provide directaccess to the plug.

2. The combination of claim 1 wherein there is space in said otherchamber between the plug and said housing structure, and includingelastomer-sealing means filling said space and extending annularly aboutsaid through opening when said opening is in registration with saidpassage.

3. The combination of claim 2 including a metallic seal ring forming aportion of said passage adjacent said plug and having metal-to-metalsealing contact with the plug, the ring acting to confine said elastomersealing means against pressure induced displacement from said space.

4. The combination of claim 2 wherein said sealing means includes upperand lower generally hemispheric extents.

5. The combination of claim 4 including a shaft connected to said plugstopper and extending to the housing exterior and adjacent saidremovable section, and operator means at the housing exterior connectedto rotate said shaft.

6. The combination of claim 5 wherein said operator means includespressure-responsive reciprocable piston structure, a housing for saidpiston structure, rack and pinion gearing operable to convertreciprocation of said piston structure to rotation of said shaft, andmeans to limit the stopper to rotate through an angle of about 90.

7. The combination of claim 6 including means to controllably supplyfluid pressure to said annular piston and to said piston structure.

8. The combination of claim 1 including operator means at one side ofsaid housing structure, there being a shaft extend ing between the plugand said operator means to transmit rotation to the plug.

9. The combination of claim 8 including an annular seal extending aboutsaid shaft to seal off against said housing structure, and another sealjoined to said annular seal extending about said plug to seal offbetween upper and lower extents of an elastomer-sealing means.

10. In a flow control assembly, the combination comprising a. a bodyhaving first and second sections forming a chamber and a stopperreceived in said chamber, the stopper having an opening extendingtherethrough and defining a first axis,

b. trunnion means mounting the stopper for rotation within the bodyabout a second axis to carry said opening into and out of flow-passingpositions, the body having inlet and outlet passages with which thestopper through opening registers in flow-passing position,

. an annulus extending about said trunnion means,

. seal ring structure having a first portion extending closely about theannulus to seal off between the annulus and body and a second portionextending about the stopper in nonsealing relation therewith to permitrotation of the stopper relative to said ring second portion while saidring second portion seals off against the body, said ring second portionbeing confined between said body first and second sections, and

e. a housing mounted by one of said sections and defining a passage inalignment with said stopper opening in its flowpassing position, and aconstrictable annulus movable in said housing between a constrictedcondition closing said passage and an expanded condition when saidpassage is open.

1. In well blowout prevention apparatus, the combination comprising a. housing structure defining vertically spaced intercommunicating chambers, b. an inwardly constrictable packer annulus in one of said chambers for forming therewith a vertical passage through which well tools may be run, c. an annular piston movable upwardly in said one chamber to constrict the annulus for sealing engagement with a well tool in said passage, d. a plug stopper having a through opening and mounted to rotate in another of said chambers to bring said through opening into and out of registration with said passage, e. said housing structure including a section at the side of the plug opposite said one chamber and which is removable to provide direct access to the plug.
 2. The combination of claim 1 wherein there is space in said other chamber between the plug and said housing structure, and including elastomer-sealing means filling said space and extending annularly about said through opening when said opening is in registration with said passage.
 3. The combination of claim 2 including a metallic seal ring forming a portion of said passage adjacent said plug and having metal-to-metal sealing contact with the plug, the ring acting to confine said elastomer sealing means against pressure induced displacement from said space.
 4. The combination of claim 2 wherein said sealing means includes upper and lower generally hemispheric extents.
 5. The combination of claim 4 including a shaft connected to said plug stopper and extending to the housing exterior and adjacent said removable section, and operator means at the housing exterior connected to rotate said shaft.
 6. The combination of claim 5 wherein said operator means includes pressure-responsive reciprocable piston structure, a housing for said piston structure, rack and pinion gearing operable to convert reciprocation of said piston structure to rotation of said shaft, and means to limit the stopper to rotate through an angle of about 90*.
 7. The combination of claim 6 including means to controllably supply fluid pressure to said annular piston and to said piston structure.
 8. The combination of claim 1 including operator means at one side of said housing structure, there being a shaft extending between the plug and said operator means to transmit rotation to the plug.
 9. The combination of claim 8 including an annular seal extending about said shaft to seal off against said housing structure, and another seal joined to said annular seal extending about said plug to seal off between upper and lower extents of an elastomer-sealing means.
 10. In a flow control assembly, the combination comprising a. a body having first and second sections forming a chamber and a stopper received in said chamber, the stopper having an opening extending therethrough and defining a first axis, b. trunnion means mounting the stopper for rotation within the body about a second axis to carry said opening into and out of flow-passing positions, the body having inlet and outlet passages with which the sTopper through opening registers in flow-passing position, c. an annulus extending about said trunnion means, d. seal ring structure having a first portion extending closely about the annulus to seal off between the annulus and body and a second portion extending about the stopper in nonsealing relation therewith to permit rotation of the stopper relative to said ring second portion while said ring second portion seals off against the body, said ring second portion being confined between said body first and second sections, and e. a housing mounted by one of said sections and defining a passage in alignment with said stopper opening in its flow-passing position, and a constrictable annulus movable in said housing between a constricted condition closing said passage and an expanded condition when said passage is open. 